The cavity of the gastrula is called

The longest gestation period among the given options is found in

The first sign of the growing foetus may be noticed by listening to the heart sound carefully through the stethoscope. The embryo's heart is formed after one month of pregnancy. Which of the following gestation periods is correctly matched?

The process by which primary germinal layers are formed is called

The human embryo is about one inch in length after (in $weeks$)

The minimum number of barriers present between foetal and maternal blood is present in which type of placenta?